This is an STTR Phase II investigation for further development and Phase III clinical trial testing for the BioMask(TM), a collagen derived ablatable material. This project is designed to clinically evaluate the BioMask(TM) at multisites and further the development of quality assurance methods used in the production of this albatable mask material. The mask material is derived from natural type I collagen which is similar to the collagen of the eye. The mask is used as an aid to laser surgery for refractive and therapeutic purposes for patients with corneal scarring and irregular astigmatism. The BioMask(TM) is a cross-linked type I collagen derivative that is solid at body temperature but becomes liquid at 45 degrees C. The mask material will be used in a randomized controlled, clinical trial to compare the efficacy and safety of BioMask(TM) assisted PTK against the current standard of care, hydroxy propyl methyl cellulose assisted PTK for patients with superficial corneal opacities and/or corneal surface irregularities. Efficacy will be measured as the number of logMAR visual acuity lines gained following the procedure and the proportion of patients gaining one or more logMAR visual acuity lines. Safety will be measured as the proportion of patients experiencing a hyperopic shift induced at 12 months after surgery, the amount of hyperopic shift induced at 12 months, and the proportion of patients losing one or more logMAR visual acuity lines. Visual acuity will be measured according to standard guidelines from the Eye Care Technology Forum. The purpose of the laboratory research efforts will be to better characterize the modified collagen material, with the intention of using this information to develop specific quality assurance methodologies. The development of such methodologies will be guided by the requirement that these procedures yield clinically valuable information yet can be effectively incorporated into a manufacturing setting. PROPOSED COMMERCIAL APPLICATION: It is anticipated that the BioMask material will enable surgeons to correct irregular astigmatism, nearsightedness, farsightedness, and errors associated with scar tissue and healed corneal ulcers. The pilot clinical study showed and 86% success rate in avoiding corneal transplants when this material was used in conjunction with the excimer laser. Other commercial applications include the use of the material as a laser calibration material, and possibly the use of the material as a synthetic corneal replacement.